A rational person starts off looking at the default positions. Then they take in information and compare that with the default position. In this case, you've already thrown out all geology for a belief in a global flood, which has no wide-scale model.

You discard evolution, which has a lot of standing, without looking at its evidence and then come up with your own idea, which you present as a theory, not even knowing specific details of evolution.

You are not rationally thinking. You don't discard most of science for a biblical worldview rationally. Most scientists believe in god. They prove that you don't have to disregard science for faith. You've disregarded details you haven't even bothered to learn. Rational? Certainly not.